SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5409ead0f4cb1dbe15087c714bd10f0b3248dd628dc5917e5c63023526399150' 
  AND token = 'rI/kVdpeqJDeC6ePpr1lK53KiPkPW7PGl26AIeDgmSM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}